The purpose of this study is to determine whether lowering of blood pressure by a combination of therapy of chlorothiazide and whole root rauwolfia is associated with a reduction in the incidence of degenerative cardio-vascular-renal complications and/or increased survival in patients with mild to moderate essential hypertension. Patients admitted to the study will be free of evidence of cardio- vascular and renal complications and other known predisposing conditions. This will be determined during an initial period of inpatient evaluation. All patients will have an average diastolic blood pressure of 90-115 mm Hg. during the 6th week of home blood pressure determinations without antihypertensive therapy. Following 3 months on placebo therapy, patients will be randomly assigned to the chlorothiazide- rauwolfia combination or an identical-appearing placebo.